Flow sensor

ABSTRACT

Flow sensors are provided that can provide both leak detection and flow monitoring. The flow monitoring enables a determination whether there are blockages or leaks in a fluid system during normal operation of the system. The leak detection enables detection of leaks when the system is shut off. The flow sensors can use a frusto-conical flow guide to provide a more compact flow sensor. The flow sensor components can be designed to retrofit existing filter assemblies.

FIELD

The present invention relates to monitoring fluid flow and, moreparticularly, to flow devices and methods for monitoring fluid flow andleaks.

BACKGROUND

Fluid systems, such as irrigation systems, are controlled by components,such as valves, upstream in the system. These control components areknown to leak from time-to-time. The leaks can be caused by debris beingcaught between the valve member and the valve seat or the results ofnormal wear and tear on the valve. Also, in many fluid systems, thereare fluid distribution devices downstream from the control components.For example, irrigation systems include water emitting devicesdownstream of the control components. These water emitting devices alsocan become defective from normal wear and tear or can be damaged fromnormal lawn care or by vandalism. As a result, excessive water isdistributed from the system. Also, the piping or conduit in such systemcan be damaged. For instance, one could unintentionally spike buriedirrigation conduits with a shovel or other tool or machine during lawncare. Further, fluid systems can develop blockage in the lines and thecomponents which will cause an undesired amount of fluid to be deliveredthrough system. With an irrigation system, this could result ininsufficient water being delivered to the vegetation. Overall, thedamage or interference with proper flow in a fluid system can result indamage and additional cost.

It is desired to have a flow sensor and method that easily and costeffectively monitors for leaks and measures flow in the fluid system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a flow sensor;

FIG. 2 is a central cross-sectional view of the flow sensor of FIG. 1;

FIG. 3 is an exploded view of the flow sensor of FIG. 1;

FIG. 4 is a perspective view of another flow sensor;

FIG. 5 is a central cross-section view of the flow sensor of FIG. 4;

FIG. 6 is an exploded view of the flow sensor of FIG. 4;

FIG. 7 is a perspective view of another flow sensor;

FIG. 8 is a central cross-section view of the flow sensor of FIG. 7;

FIG. 9 is an exploded view of the flow sensor of FIG. 7;

FIG. 10 is a bottom perspective view of a top cover of the flow sensorof FIG. 7;

FIG. 11 is a top perspective view of an intermediate cover of the flowsensor of FIG. 7;

FIG. 12 is a top perspective view of a base of the flow sensor of FIG.7;

FIG. 13 is a bottom perspective view of a funnel of the flow sensor ofFIG. 7;

FIG. 14 is a top perspective view of a piston, top cap, and rotatingstrip of the flow sensor of FIG. 7;

FIG. 15 is a perspective view of the top cap and piston of the flowsensor of FIG. 7;

FIG. 16 is a bottom perspective view of a shaft cap of the flow sensorof FIG. 7;

FIG. 17 is a central cross-section view of another flow sensor;

FIG. 18 is a perspective view of a filter of the flow sensor of FIG. 17;

FIG. 19 is a perspective view of an alternate flow sensor;

FIG. 20 is an exploded view of an inlet, an outlet, and a flow sensorbody of the flow sensor of FIG. 19;

FIG. 21 is a central cross-sectional view of the flow sensor of FIG. 19;

FIG. 22 is an exploded view of a portion of the flow sensor of FIG. 19;

FIG. 23 is a partial cross-sectional view of the body and a flow guideof the flow sensor of FIG. 19;

FIG. 24 is a bottom perspective view of the flow guide of the flowsensor of FIG. 19;

FIG. 25 is a top perspective view of the body of the flow sensor of FIG.19;

FIG. 26 is a top perspective, exploded view of a piston of the flowsensor of FIG. 19;

FIG. 27 is a top perspective view of a twisted shaft of the flow sensorof FIG. 19 and the piston of FIG. 26;

FIG. 28 is a top perspective, cross-sectional view of a washer of theflow sensor of FIG. 19;

FIG. 29 is a central cross-sectional view of an enclosure of the flowsensor of FIG. 19 and the washer of FIG. 28;

FIG. 30 is a bottom plan view of the enclosure of FIG. 29;

FIG. 31 is a bottom perspective view of the enclosure of FIG. 29;

FIG. 32 is a forward of center cross-sectional, perspective view of theenclosure, the twisted shaft, a helical spring, and the piston of theflow sensor of FIG. 19;

FIG. 33 is a side perspective view of a spindle of the flow sensor ofFIG. 19;

FIG. 34 is a central cross-sectional view of the spindle of FIG. 33 anda lock clip and a seal of the flow sensor of FIG. 19 associated with thespindle;

FIG. 35 is a perspective view of a dial assembly of the flow sensor ofFIG. 19;

FIG. 36 is a top perspective view of a top cover of the flow sensor ofFIG. 19;

FIG. 37 is a central cross-sectional view of the flow sensor of FIG. 19with a cylindrical flow guide;

FIG. 38 is a bottom perspective view of the cylindrical flow guide ofFIG. 37;

FIG. 39 is a central cross-sectional view of an alternative flow sensor;

FIG. 40 is an exploded view of a portion of the flow sensor of FIG. 39;

FIG. 41 is a cross-sectional view of a body and a single piece flowguide/filter of the flow sensor of FIG. 39;

FIG. 42 is a bottom perspective view of the single piece flowguide/filter of the flow sensor of FIG. 39;

FIG. 43 is a central cross-sectional view of the single piece flowguide/filter of FIG. 42;

FIG. 44 is a top perspective view of the body of the flow sensor of FIG.39;

FIG. 45 is a top perspective, central cross-sectional view of a washerof the flow sensor of FIG. 39;

FIG. 46 is a central cross-sectional view of a top cover of the flowsensor of FIG. 39 and the washer of FIG. 45;

FIG. 47 is a bottom perspective view of the top cover of FIG. 46;

FIG. 48 is a bottom plan view of the top cover of FIG. 46;

FIG. 49 is a perspective view of a dial assembly of the flow sensor ofFIG. 39;

FIG. 50 is a side perspective view of the top cover, the dial assemblyand a flow gauge of the flow sensor of FIG. 39;

FIG. 51 is a top perspective view of the top cover of the flow sensor ofFIG. 39;

FIG. 52 is a bottom perspective view of a dial seat of the dial assemblyof FIG. 49;

FIG. 53 is a side perspective view of the flow gauge of FIG. 50;

FIG. 54 is an exploded view of an alternative top cover, flow gauge anddial assembly;

FIG. 55 is an exploded view of the flow gauge of FIG. 54;

FIG. 56 is side perspective view of the top cover, flow gauge and dialassembly of FIG. 54;

FIG. 57 is a cross-sectional view of the top cover, flow gauge and dialassembly of FIG. 54; and

FIG. 58 is a bottom plan view of top cover of FIG. 54.

DETAILED DESCRIPTION

Referring to FIGS. 1-3, there is shown a flow sensor 10. The flow sensor10 can be embedded into a fluid system, such as an irrigation system.The flow sensor 10 includes an inlet 12 portion, a leak detector 14, aflow meter 16 and an outlet portion 18. The leak detector 14 monitorsupstream components, such as a valve, for leaks. The flow meter 16monitors flow to detect whether the flow is above or below a normalamount or range for the system. For example, in an irrigation system, ifthe flow is above a normal amount or range, this indicates that there isa leak downstream in the system, such as in the conduit and/or wateringemission device(s). On the other hand, if the flow is below thepredetermined amount, this indicates that there may be a clog in thesystem, such as in the flow conduit and/or watering emission device(s)or that the valve upstream is not operating properly.

The inlet portion 12 and the outlet portion 18 are configured forattachment of the flow sensor 10 to conduit in the system. Asillustrated, the inlet portion 12 includes exterior threading 20, whichcan be male NPT thread, for being threaded into an interior threadedconduit end. The outlet portion 18 includes internal threading 22, whichcan be female NPT thread, for cooperating with external threading on adownstream conduit end. Alternatively, the inlet portion and outletportion could both be male threaded or female threaded. Also, instead ofthreading, the inlet portion and the outlet portion could have smoothsurfaces that are glued to the inner and outer surfaces of the upstreamconduit and downstream conduit, respectively. The inlet portion 12extends from the leak detector 14, and the outlet portion 18 extendsfrom a portion of the flow meter 16.

The leak detector 14 includes a housing 24 disposed between the inletportion 12 and the flow sensor 16. The housing 24 can be a two piecehousing with an upstream portion 24 a and a downstream portion 24 b.Alternatively, the housing could be one piece. The housing 24 includes alower portion 26 that provides a flow passage 28 to the flow meter 16and an upper portion 34 that provides a leak indicator system 30.

The leak detector 14 includes a chamber 32 extending upward from thelower portion 26 of the housing 24. The chamber 32 is defined by theupper portion 34 of the housing 24 and includes a transparent upperportion 34 a and an opaque or semi-transparent lower portion 34 b.Alternatively, as explained further below, the upper portion 34 a andthe lower portion 34 b both could be opaque or semi-transparent, and athird portion 34 c in between the upper and lower portions 34 a, 34 bcould be transparent. The leak detector 14 further includes a flowindicator 36 and a spring 38 disposed on a shaft 40. The shaft 40includes a head 42 that is used to pin the shaft 40 to an upper end 44of the upper portion 34 of the housing 24. The spring 38 is disposedbetween the upper end 44 of the chamber 32 and the flow indicator 36 tobias the flow indicator 36 down into the opaque portion 34 b of thechamber 32.

The chamber 32 is able to receive fluid flow from the passage 28. Morespecifically, the housing 24 forms an annular chamber 33 and defines afirst opening 35 to the annular chamber 33 from the flow passage 28. Thefirst opening 35 is located diametrically opposite from the chamber 32.The annular chamber 33 has a second opening 37 at the annular chamber33. Fluid flows from the passage 28 through the first opening 35, aroundthe annular chamber 33 (through one or both sides) and, then, throughthe second opening 37 into the chamber 32 of the leak detector 14. Adrain passage 46 is on the downstream side of the chamber 32. The drainpassage 46 dumps fluid flowing through the leak detector 14 into theflow meter 16.

In operation, when pressurized flow of fluid to the flow sensor 10 isdiscontinued, the flow meter 16 closes so that fluid cannot flow furtherdownstream, such as due to gravity. If flow continues on the upstreamside, it will flow through the annular chamber 33 and cause the flowindicator 36 to rise upward in the chamber 32 against the bias of thespring 38. The spring force is selected so that the flow indicator 36can detect very small amounts of flow, such as that from a leakingcontrol valve of an irrigation system. When there is a leak, the flowindicator 36 will rise up on the shaft 40 in the chamber 32 into thetransparent portion 34 a of the upper portion 34 or in another form ofthe embodiment into the transparent portion 34 c. The flow indicator 36can be of a color, such as red, that is easily seen through thetransparent portion 34 a or 34 c of the upper portion 34.

When the system is operating normally, the flow indicator 36 does notindicate a leak situation. In one embodiment, the chamber 32 can bebypassed by the flow through the sensor 10. To do so, the second inlet32 to the chamber 32 can be oriented to face downstream or the housing24 can be angled upstream, or both features can be used. This upstreamorientation renders it difficult for the downstream moving flow to forman upstream flow to access the chamber 32. Also, the second opening 37can be made relatively small. In another embodiment, the second inlet 37could allow flow into the chamber 37, but the housing 24 would havethree portions, as mentioned above. The lower and upper opaque orsemi-transparent portions 34 a, 34 b and the transparent center portion34 c between portions 34 a, 34 b. When flow is flowing normally, theflow also would flow through the leak detector 14 moving the flowindicator 36 up to the upper opaque portion 34 a. When the flow is off,the flow indicator 36 moves to the lower opaque portion 34 b. If thereis a leak detected, the flow indicator 36 would move to the transparentcenter portion 34 c.

The flow meter 16 includes a conical housing 48 that enlarges in thedownstream direction and can be transparent. The flow meter 16 furtherincludes a piston 50 connected to one end of a shaft 52 and spring 54disposed about the shaft 52. More specifically, the piston 50 is held atthe end of shaft 52 by a shaft head 53 and the spring 54. The piston 50is disc shaped but can be any other shape that restricts flow. Theoutlet portion 18 includes a center hub 56 that is supported by one ormore radial spikes. In the illustrated embodiment, there are threeradial spokes 58 interconnecting the hub 56 and the outlet portion 18.The hub 56 includes a central passage 60 through which the shaft 52translates as the piston 50 moves back and forth. Alternatively, theshaft 52 could be fixed against movement relative to the passage 60, andthe piston 50 could reciprocate along the shaft 52. In this alternateembodiment, the piston 50 would not be fixed to the end of the shaft 52.The spring 54 engages the piston 50 and an enlarged landing 63 on thecentral hub 56 to bias the piston 50 toward a seat 62 formed about theinner perimeter of the downstream side of the housing 24 of the leakdetector 14.

The piston 50, the spring 54 and the conical housing 48 are coordinatedto measure flow through the conical housing 48. Since the piston 50 hasa constant diameter, the radial distance between a perimeter 51 of thepiston 50 and the conical housing 48 increases as the piston 50translates downstream. This enables the flow meter to have a reducedoverall length when compared to a constant diameter housing. Morespecifically, in general, higher velocities mean a higher force on thepiston 50. For an expanding area, such as that provided by the conicalhousing 48, the velocity will decrease over the length for a given flowrate. So, at higher flow rates, the piston 50 will be located in asection of the conical housing 48 with a larger cross-sectional area,and therefore, have a lower velocity. The advantage is that the flowmeter can be shorter for the same flow rate range, and there will be alower pressure drop.

The foregoing is illustrated by the following examples. In a firstexample, the conical housing has an inlet diameter of 1.0 in., an outletdiameter of 1.48 in., and an axial length of 1.8 in. The piston has adiameter of 0.97 in., and the spring rate is 0.50 lb/in. In operation,the following table shows the piston position from the inlet and thespring displacement for 5.0 gpm and 20.0 gpm flow rates.

Flow Rate Piston Position From Spring Displacement (gpm) Inlet (in.)(in.) 5.0 0.52 0.52 20.0 1.75 1.75

In a second example for comparison, a straight housing has a diameter of1.0. The piston has a diameter of 0.97, and a spring rate of 0.50. Inoperation, the following table shows the spring displacement for 1.0 gpmand 20.0 gpm flow rates.

Flow Rate (gpm) Spring Displacement (in.) 5.0 0.52 20.0 8.33

The comparison of the spring displacements demonstrates that the conicalhousing can be much shorter than the straight housing. For a flow rateof 20.0 gpm, the conical housing has a spring displacement of 1.75 in.versus 8.33 in. for the straight housing.

When there is no pressurized flow in the system, the piston 50 rests onthe seat 52 and prevents flow from draining downstream in the system.The seat 52 or the upstream surface of the piston 50 that engages theseat 52 could include an elastomeric material that enhances the sealbetween the two. In this position, the drain passage 46 of the flowdetector dumps fluid flowing through the leak detector 14 into the flowmeter 16 downstream of the piston 50.

When pressurized flow is on, the piston 50 moves downstream a distancedependent on the flow amount. The piston 50 movement can be visualizedthrough the transparent conical housing 48. When the system is operatingnormally, the piston 50 moves downstream about same amount every timethe system is pressurized. There may be slight variations in thedistances due to supply pressure fluctuations. This distance or rangecan be saved using a sliding indicator 64 on the top of the conicalhousing 48.

More specifically, the top of the conical housing 48 includes a lineartrack 66 having a predetermined cross-section. The bottom of the slidingindicator 64 includes a complementary slot 68 to receive and translatealong the track 66. As illustrated, the track 66 can have a T-shapecross-section, but other cross-sections can be used as well. There issufficient friction between the linear track 66 and the slot 68 so thatthe sliding indicator 64 does not inadvertently translate. Also, a setscrew (not shown) can be threaded through a hole in the slidingindicator 64 to engage the track 66 to further prevent unintentionalmovement of the sliding indicator 64 along the track 66. The set screwcan include a head configured for use with only a tool, such as an Allenwrench or screwdriver. This will help prevent unintentional movement ofthe slider because the slider will require a tool to be loosened andnormal vibrating will not cause the slider to move inadvertently. Thesliding indicator 64 also defines a window 70 that one can use to centerthe sliding indicator 64 over the piston 50 to record the location ofthe piston 50 when the fluid system is operating normally. Thispositioning may be checked over a few iterations of turning on and offthe system over a couple of days to account for fluctuations in supplypressure. Further, the track 66 can include a scale 65 indicating aparticular number of gallons per minute or hour flowing through the flowsensor 10. Due to the conical design of the housing 48, the scale maynot be linear in that the tick mark spacing may vary and become closertowards one end.

The sliding indicator 64 also may include coloring to aid in determiningthe operation of the fluid system. For example, sides 72 of the window70 may be colored green to indicate proper operation, and ends 74 of thewindow 70 may be colored red to indicate improper operation. When thepiston 50 is positioned in the window 70 along the green sides 70 of thewindow, the system is operating normally. On the other hand, when thepiston 50 is downstream of the red on the downstream end 74 of thewindow 70, this would indicate that there is too much flow through thesystem. Accordingly, the system should be checked for leaks. In anirrigation system, for instance, the excess flow could be a nozzlemissing from a sprinkler device or breaks in the conduit. Similarly,when the piston 50 is upstream of the red on the upstream end 74 of thewindow 70, this would indicate that there is insufficient flow throughthe system. The system should be checked to make sure that there are noclogs upstream and downstream in the system. In an irrigation system,one should check to make sure the upstream valve is operating properlyto provide proper flow and that there are no downstream irrigationdevices that are failing or working improperly, such as being clogged.

Referring to FIGS. 4-6, there is shown another flow sensor 110. The flowsensor 110 also can be embedded into a fluid system, such as anirrigation system. The flow sensor 110 includes an inlet 112 portion, aleak detector 114, a flow meter 116 and an outlet portion 118. The leakdetector 114 monitors upstream components, such as a valve, for leaks.The flow meter 116 monitors flow to detect whether the flow is above orbelow a normal amount or range for the system. For example, in anirrigation system, if the flow is above a normal amount or range, thisindicates that there is a leak downstream in the system, such as in theconduit and/or watering emission device(s). On the other hand, if theflow is below the predetermined amount, this indicates that there may bea clog in the system, such as in the flow conduit and/or wateringemission device(s) or that the valve upstream is not operating properly.

The inlet portion 112 and the outlet portion 118 are configured forattachment of the flow sensor 10 to conduit in the system. Asillustrated, the inlet portion 112 includes exterior threading 120,which can be male NPT thread, for being threaded into an interiorthreaded conduit end. The outlet portion 118 includes internal threading122, which can be female NPT thread, for cooperating with externalthreading on a downstream conduit end. Alternatively, the inlet portionand outlet portion could both be male threaded or female threaded. Also,instead of threading, the inlet portion and the outlet portion couldhave smooth surfaces that are glued to the inner and outer surfaces ofthe upstream conduit and downstream conduit, respectively. The inletportion 112 extends from the leak detector 114, and the outlet portion118 extends from a portion of the flow meter 116.

The leak detector 114 includes a housing 124 disposed between the inletportion 112 and the flow meter 116. The housing 124 can be a two piecehousing with an upstream portion 124 a and a downstream portion 124 b.The leak detector also can be a single piece. The housing 124 includes alower portion 126 that provides a flow passage 128 to the flow meter 116and an upper portion 134 that provides a leak indicator system 130.

The leak detector 114 includes a chamber 132 extending upward from thelower portion 126 of the housing 124. The chamber 132 is defined by theupper portion 134 of the housing 124 and includes a transparent upperportion 134 a and an opaque or semi-transparent lower portion 134 b.Alternatively, as with the previous embodiment, the upper portion 134 aand the lower portion 134 b both could be opaque or semi-transparent,and a third portion 134 c in between the upper and lower portions 134 a,134 b could be transparent. The leak detector 114 further includes aflow indicator 136 and a spring 138 disposed on a shaft 140. The shaft140 includes a head 142 that is used to pin the shaft 140 to an upperend 144 of the upper portion 134 of the housing 124. The spring 138 isdisposed between the upper end 144 of the chamber 132 and the flowindicator 136 to bias the flow indicator 136 down into the opaqueportion 134 b of the chamber 132.

The chamber 132 is able to receive fluid flow from the passage 128. Morespecifically, the housing 124 forms an annular chamber 133 and defines afirst opening 135 to the annular chamber 133 from the flow passage 128.The first opening 135 is located diametrically opposite from the chamber132. The annular chamber 133 has a second opening 137 at the annularchamber 133. Fluid flows from the passage 128 through the first opening135, around the annular chamber 133 (through one or both sides) and,then, through the second opening 137 into the chamber 132 of the leakdetector 114. A drain passage 146 is on the downstream side of thechamber 132. The drain passage 146 dumps fluid flowing through the leakdetector 114 into the flow meter 116.

In operation, when pressurized flow of fluid to the flow sensor 110 isdiscontinued, the flow meter 116 closes so that fluid cannot flowfurther downstream, such as due to gravity. If flow continues on theupstream side, it will flow through the annular chamber 133 and causethe flow indicator 136 to rise upward in the chamber 132 against thebias of the spring 138. The spring force is selected so that the flowindicator 136 can detect very small amounts of flow, such as that from aleaking control valve of an irrigation system. When there is a leak, theflow indicator 136 will rise up on the shaft 140 in the chamber 132 intothe transparent portion 134 a of the upper portion 134 or in anotherform of the embodiment into the transparent portion 134 c. The flowindicator 136 can be of a color, such as red, that is easily seenthrough the transparent portion 134 a or 134 c of the upper portion 134,depending on the design.

When the system is operating normally, the flow indicator 136 does notindicate a leak situation. In one embodiment, the chamber 132 can bebypassed by the flow through the sensor 110. To do so, the second inlet132 to the chamber 132 can be oriented to face downstream or the housing124 can be angled upstream, or both features can be used. This upstreamorientation renders it difficult for the downstream moving flow to forman upstream flow to access the chamber 132. Also, the second opening 137can be made relatively small. In another embodiment, the second inlet137 could allow flow into the chamber 137, but the housing 124 wouldhave three portions, as mentioned above. The lower and upper opaque orsemi-transparent portions 134 a, 134 b and the transparent centerportion 134 c between portions 134 a, 134 b. When flow is flowingnormally, the flow also would flow through the leak detector 114 movingthe flow indicator 136 up to the upper opaque portion 134 a. When theflow is off, the flow indicator 136 moves to the lower opaque portion134 b. If there is a leak detected, the flow indicator 136 would move tothe transparent center portion 134 c.

The flow meter 116 includes a conical housing 148 that enlarges in thedownstream direction and can be transparent. An upper housing 150extends from the conical housing 148 and is transparent. The upperhousing 150 includes a pair of depending hinge points 152 used with ahinge pin 154 to attach a valve door 156, a torsional spring 158 and aflow indicator 160 to the upper housing 150. The valve door 156 pivotsincludes a pair of arms 157 that define hinge holes at their ends, andthe valve door 156 pivots about the hinge pin 154 depending on theamount of flow through the conical housing 148. The valve door 156 isgenerally disc shaped. The spring 158 includes a center portion thatforms a loop 162 that wraps around a post 164 projecting from adownstream side 166 of the valve door 156. The spring 158 has a coil 168on each side of the loop 162 that each terminates with a tail portion170 that engages an upstream inner surface 172 of the upper housing 150.The hinge pin 154 extends through the coils 168. The spring 158 biasesthe valve door 156 in the upstream direction toward a seat 161 formedabout the inner perimeter of the downstream side of the housing 24 ofthe leak detector 14. The valve door 156 moves the flow indicator 160depending on the flow through conical housing 148.

More specifically, the flow indicator 160 has a first linear leg 162with one end caring an adjustment pin 176 that engages the downstreamside 166 of the valve door 156 below the post 164 and the other endforming a pivot hole 178 for the hinge pin 154. The pivot hole 178receives the hinge pin 154 between the coils 168 of the spring 158. Theadjustment pin 176 could be adjustable (e.g., a set screw) in the firstlinear leg 162 to calibrate the flow indicator 160. The flow indicator160 has a second linear leg 180 that extends downstream from the pivothole 178 to an arcuate leg 182 that curves upstream. The arcuate leg 182moves in the upper housing 150 to provide a visual indication of theflow.

The valve door 156, the spring 158 and the conical housing 148 arecoordinated to measure flow through the conical housing 148. Since thevalve door 156 is circular with a constant diameter, the radial distancebetween a perimeter 184 of the piston valve door 156 and the conicalhousing 148 increases as the valve door 156 pivots downstream. Similarto the piston embodiment above, as the door 156 pivots downstream, thearea increases, and the velocity decreases. Also, as the door 156 pivotsdownstream, there will be less drag on the door so its movementincrements will become smaller as the flow increases. This enables theflow meter to have a reduced overall length when compared to a constantdiameter housing. When there is no pressurized flow in the system, thevalve door 156 rests on the seat 161 and prevents flow from drainingdownstream in the system. The seat 161 or an upstream surface 186 of thevalve door 156 that engages the seat 161 could include an elastomericmaterial that enhances the seal between the two. In this position, thedrain passage 146 of the leak detector dumps fluid flowing through theleak detector into the flow meter 116 downstream of the valve door 156.

When pressurized flow is on, the valve door 156 pivots downstream anamount dependent on the flow amount. The valve door 156 movement can bevisualized by reference to the corresponding movement of the arcuate leg182 of the flow indicator 160 through the transparent upper housing 150.When the system is operating normally, the valve door 156 pivotsdownstream about same amount every time the system is pressurized. Theremay be slight variations in the amount due to supply pressurefluctuations. This pivot amount can be saved using a sliding indicatoron the top of the upper housing 150. While this sliding indicator is notshown, it can be the same design as that for the flow sensor 10. In sum,the top of the upper housing can include a track with a particularcross-section, such as a T shape cross-section. The track would tracethe arc across the top of the upper housing 150. Other cross-sectionscan be used as well. The bottom of the sliding indicator includes acomplementary slot to the track so that it can receive and translatealong the track. A set screw with a tool configured head can be used tolock the sliding indicator in place. The sliding indicator also definesa window that one can use to center the sliding indicator over aterminal end 188 of the arcuate leg 182 of the flow indicator 136 whenthe fluid system is operating normally. Further, the track can include ascale indicating a particular number of gallons per minute or hourflowing through the flow sensor 110. Due to the conical design of thehousing 148, the scale may not be linear in that the tick mark spacingmay vary and become closer towards one end. Other designs could beemployed as well. For example, the pivoting of the door could betranslated into a linear movement or movement of a dial indicator.

As with flow sensor 10, the sliding indicator also may include coloringto aid in determining the operation of the fluid system. For example,sides of the window may be colored green to indicate proper operation,and ends of the window may be colored red to indicate improperoperation. When the terminal end 188 of the flow indicator 160 ispositioned in the window along the green sides of the window, the systemis operating normally. On the other hand, when the terminal end 188 ofthe flow indicator 160 is downstream of the red on the downstream end ofthe window, this would indicate that there is too much flow through thesystem. Accordingly, the system should be checked for leaks. In anirrigation system, for instance, the excess flow could be a nozzlemissing from a sprinkler device or breaks in the conduit. Similarly,when the terminal end 188 of the flow indicator 160 is upstream of thered on the upstream end of the window, this would indicate that there isinsufficient flow through the system. The system should be checked tomake sure that there are no clogs upstream and downstream in the system.In an irrigation system, one should check to make sure the upstreamvalve is operating properly to provide proper flow and that there are nodownstream irrigation devices that are failing or working improperly,such as being clogged.

With reference to FIGS. 7-18, there is shown a flow sensor 210. The flowsensor 210 can be embedded into a fluid system, such as an irrigationsystem. The flow sensor 210 includes an inlet 212, a flow meter 214 andan outlet 216. The flow meter 214 monitors flow to detect whether theflow is above or below a normal amount or range for a current state ofthe system. For example, in an irrigation system, if the flow is above anormal amount or range, this indicates that there is a leak downstreamin the system, such as in the conduit and/or watering emissiondevice(s). On the other hand, if the flow is below the predeterminedamount, this indicates that there may be a clog in the system, such asin the flow conduit and/or watering emission device(s) or that the valveupstream is not operating properly.

The inlet 212 and the outlet 216 are configured for attachment of theflow sensor 210 to conduit in the system. As illustrated, the inlet 212includes exterior threading 218, which can be male NPT threading, forbeing threaded into an interior threaded conduit end. The inlet 212 alsoincludes a flange 220 for attachment to a base 222 of the flow meter214. The base 222 includes a corresponding flange 224. The flanges 222,224 include holes 226 that align and are used to secure the flanges 222,224 using bolts 228, nuts 230 and washers 232. The washers could be lockwashers. The flange 220 includes a recess 231 for holding an o-ring 233to further seal the interface between the flanges 220, 224.

The outlet 216 includes internal threading 234, which can be female NPTthreading, for cooperating with external threading on a downstreamconduit end. The outlet 216 also includes a flange 236 for attachment tothe base 222 of the flow meter 214. The base 222 includes acorresponding flange 238. The flanges 234, 236 include holes 240 thatalign and are used to secure the flanges 234, 236 using bolts 228, nuts230 and washers 232. The flange 238 includes a recess 239 for holding ano-ring 241 to further seal the interface between the flanges 236, 238.

The inlet 212 and the outlet 216 each include an annular flange 251, 253that draws the inlet 212 and the outlet 216 into a sealing engagementwith an o-ring 255 disposed in an annular recess 257 and each end of thebody 222 facing the inlet 212 and the outlet 216. This quick connectalternative enables the inlet and outlet to be interchangeable toaccommodate different connections and pipe sizes. For example, the inletand outlet could both be male threaded or female threaded. Also, insteadof threading, the inlet and the outlet could have smooth surfaces thatare glued to the inner and outer surfaces of the upstream conduit anddownstream conduit, respectively.

Alternatively, in place of flanges 222, 224, the base 222 could includethreaded inlets and outlets for receiving threaded collars as describedlater in connection with the embodiment of FIGS. 19-36.

The flow meter 214 includes the base 222, an intermediate cover 242 anda top cover 244. The top cover 244 includes a flange 246 for attachmentto a flange 248 of the intermediate cover 242. The flanges 246, 248include holes 250 that align and are used to secure the flanges 246, 248using bolts 228, nuts 230 and washers 232. The flange 246 includes arecess 247 for holding an o-ring 249 to further seal the interfacebetween the flanges 246, 248.

The intermediate cover 242 attaches to the base 222. The intermediatecover 242 includes radial tabs 252 that each define a hole 254 thataligns with a corresponding hole 256 defined by each bore portion 258 ofthe base 222. A threaded screw 260 extends through each of the holes 254of the radial tabs 252 and threads into the hole 256 of each of the boreportions 258 of the base 222. Alternatively, the base 222 and theintermediate cover 242 could be a single piece.

The base 222 defines an inlet passage 262 and an outlet passage 264. Theinlet passage 262 is defined in part by an upward directed tubularportion 266 at the center of the base 222. The outlet passage 262extends around the tubular portion 266 and over a portion of the inletpassage 262 upstream of the tubular portion 266. The base 222 alsodefines an annular recess 268 adjacent and radially inside of the boreportions 258. The annular recess 268 holds an o-ring 270 that sealsagainst the intermediate cover 242.

The intermediate cover 242 has an inward tapering configuration towardsthe base 222. The intermediate cover forms a lower chamber 272 and incombination with the top cover 244 defines an upper chamber 274. Thelower chamber 272 houses a flow guide 276. The flow guide 276 includes atubular portion 278 and a frusto-conical portion 280. The flow guidetubular portion 278 extends into the tubular portion 266 of the inletpassage 262. The flow guide tubular portion 278 includes an annularrecess 282 about its exterior surface that receives an annular rib 284projecting from an interior surface of the inlet passage tubular portion266. This secures flow guide 276 at the base 222. An o-ring 286 isdisposed between the exterior surface of the flow guide tubular portion278 and the interior surface of the inlet passage tubular portion 266 toprovide a seal between the two components. The o-ring 286 is held in anannular recess 288 formed in the outer surface of the flow guide 276.The flow guide 276 defines an axially extending slot 290 at its tubularportion 278. The slot 290 receives an axially extending rib 292projecting from the inlet passage tubular portion 266 of the base 222.The slot 290 and rib 292 align the flow guide 276 for proper orientationduring assembly of the flow guide 276 to the base 222.

The frusto-conical portion 280 of the flow guide 276 allows fluid toflow outward as it moves to the top of the upper chamber 274. Thefrusto-conical portion 280 may terminate with an upper edge 306 that iscurled outward and downward to assist with a smooth transition for theflow from the flow guide 276 down toward the outlet passage. For furtherassistance in redirecting the flow fluid, the upper chamber 274 includesan arcuate, annular portion 294. The spacing between the outward flareand curled upper edge of the frusto-conical portion 280, on the onehand, and the smooth curvature of the arcuate, annular portion 294 ofthe upper chamber 274, on the other hand, can be optimized so thatpressure drop is reduced. For example, it has been found that reducingthe spacing can minimize the pressure drop.

A piston 296 operates in the both the lower and upper chambers 272, 274of the intermediate cover 242. The piston 296 includes a shaft 298 andan enlarged head 300. The enlarged head 300 operates in the flow guide276 and fits into the flow guide tubular portion 278 with sufficientclearance so that fluid can flow around the enlarged head 300 to be moresensitive to low flow rates so that they can be measured when theenlarged head 300 is in the flow guide tubular portion 278. The enlargedhead 300 includes small radial projections 302 that engage the innersurface of the flow guide tubular portion 278 to center the enlargedhead 300 in the flow guide tubular portion 278 and to reduce frictionbetween the enlarged head 300 and the inner surface of the flow guidetubular portion 278 when the piston 296 moves. Also, when the enlargedhead 300 is located in the flow guide tubular portion 278, it can reston a series of tapered ribs 304 extending from the inner surface of theflow guide tubular portion 278 when there is no flow. Alternatively, thetapered ribs 304 could be replaced with a continuous, annular projectingsealing seat for the enlarged head to rest on when there is no flow.

The shaft 298 has a hollow interior 308 and extends through an opening310 at the top of the intermediate cover 242. The intermediate cover 242includes a tubular portion 312 that extends about the opening 310 andfrom the opening 310 to the flange 246. The opening 310 is sized toprovide enough clearance so the shaft 298 can reciprocate easily throughthe opening 310. The opening 310 includes a rib 311 extending inward tobe received in longitudinal extending slot 313 in an outer surface ofthe shaft 298 of the piston 296. The rib 311 and the slot 313 preventthe piston 296 from rotating.

While fluid can fill the upper chamber 274, the upper chamber 274 is notin the path of the primary flow through the flow meter 214. This reducesthe potential for debris to be carried into the upper chamber 274 andaffect the operation of an instrument 314 housed in the upper chamber214 that indicates the amount of flow passing through the flow meter214.

Alternatively, as shown in FIG. 17, an o-ring 316 may be incorporatedinto an interface between the opening 310 and the shaft 298 to sealagainst fluid entering the upper chamber 274. The intermediate cover 242may define an annular recess 318 about the opening 310 to hold theo-ring 316. The o-ring could be the Turcon® Double Delta® and/or made ofthe material Zrucon® 280. Both are provided by Trelleborg SealingSolutions of Helsingor, Denmark. The other o-rings discussed hereincould be of the same material.

The instrument 314 includes a twisted shaft 320. One end fitted of thetwisted shaft 320 has a dial 322, and the other end fits through a slot324 defined by a cap 326. The cap 326 is attached to the end of theshaft 298 opposite the enlarged head 300. As the shaft 298 moves upwardin the upper chamber 274 as flow increases, the twisted shaft 320 movesfurther into the hollow interior 308 of the shaft 298. The twist in thetwisted shaft 320 turns the twisted shaft 320 and dial 322 as thetwisted shaft 320 moves into the hollow interior 308 as flow through theflow meter 214 increases. A conical tip 328 extends from a centerposition of the dial 322 and pivots in a conical dimple 331 on an insidesurface 330 of a top wall 332 of the top cover 244 as the dial 322rotates. The interior of the top cover 244 and the tubular portion 312of the intermediate cover 242 include a number of longitudinal ribs 333,335, respectively, extending into the upper chamber 274. The dial 322translates along the ribs 333, 335. The conical tip 328 and the ribs333, 335 reduce friction for the operation of the instrument 314 andguide the piston 296 to reduce side loading on the piston 296 when flowthrough the flow meter 214 is non-symmetrical.

The top wall 332 of the top cover 244 can be transparent to allow visualinspection of the dial 322. The dial 322 and the top wall 332 caninclude markings that indicate the flow. For example, the dial 322 mayinclude a marking, such as an arrow 334, and the wall 332 may include ascale 336 showing different pressures. A spring 338 in the upper chamber274 biases the piston 296 downward toward the inlet passage 262. Thespring 338 seats in an annular recess 340 at the top of the upperchamber 274 and an annular recess 342 in the shaft cap 326 at the bottomof the upper chamber 274.

The shaft 298 and the shaft cap 326 are splined together such that theydo not rotate relative to one another. The shaft 298 includes alongitudinal rib 344 extending into the hollow interior 308. The rib 344is received in a slot 346 defined by a tubular extension 348 extendingfrom a bottom of the shaft cap 326 that is received in the hollowinterior 308 of the shaft 298. The rib 344 and slot 346 spline the shaft298 and the shaft cap 326 together. The tubular extension 348 can have astepped configuration where the portion adjacent the bottom of the shaftcap 326 is larger in diameter and forms a friction fit with an innersurface of the shaft 298. In addition to a friction fit between thetubular extension 348 of the shaft cap 326 and the shaft 298, the shaftcap 326 and the shaft 298 also could be glued or welded together. Theshaft cap 326 defines a number of holes 350 to allow water and air topass through the shaft cap 326 as it reciprocates in the upper chamber274. The holes 350 prevent pressure buildup on the shaft cap 326 thatwould otherwise affect movement of the piston 296 and the correspondingfluid measurement.

As shown in FIGS. 17 and 18, a filter 352 also may be included to removedebris from fluid before it passes to the outlet passage 264. The filter352 can be secured in the lower chamber 272 between an annular landing354 inward of the recess 268 for the o-ring 270 of the base 222 and thecurled upper edge 306 of the flow guide 276. The filter 352 can includea top ring 356, a bottom ring 358 and a series of filter supportelements 360 extending between the top ring 356 and the bottom ring 358.A mesh or screen 361 could be fixed to the top ring 356, the bottom ring358 and the filter support elements 360. For example, the mesh or screencould be over-molded onto the top ring 356, the bottom ring 358 and thefilter support elements 360. The bottom ring 358 can include a radialflange 362 that can be received in a recess 364 defined by theintermediate cover 242 at the interface with the base 222 to furthersecure the filter 352.

In operation, fluid flows into the flow sensor 210 through the inletpassage 262. As the flow increases, the fluid moves the piston upwardsin the lower and upper chambers 272, 274. The piston causes theinstrument 314 to determine the flow rate through the flow sensor 210.That is, the upward movement of the piston 296 against the spring 338causes the twisted shaft 320 to turn and twist into the hollow interior308 of the shaft 298. The twisting of the twisted shaft 320 rotates thedial 322 causing the arrow 334 to rotate about the scale 336 indicatingthe flow through the flow meter 214 of the flow sensor 210. As the flowmeter 214 is measuring the flow, the fluid flows around the enlargedhead 300 of the piston 296 and through the flow guide 276. Then, theflow is guided by the accurate, annular portion 294 of the intermediatecover 242 and the curled edge 306 of the flow guide 276 to turndirection back towards the outlet passage 264.

The piston 296, the spring 338 and the frusto-conical portion 280 of theflow guide 276 are coordinated to measure flow through flow meter 214.Since the enlarged head 300 of the piston 296 has a constant diameter,the radial distance between a perimeter of the enlarged head 300 and thefrusto-conical portion 280 of the flow guide 276 increases as the piston296 translates downstream. This enables the flow meter 214 to have areduced overall length (or height) when compared to a constant diameterflow guide. More specifically, in general, higher velocities mean ahigher force on the enlarged head 300 of the piston 296. For anexpanding area, such as that provided by the frusto-conical portion 280of the flow guide 276, the velocity will decrease over the length for agiven flow rate. So, at higher flow rates, the enlarged head 300 will belocated in a section of the frusto-conical portion 280 with a largercross-sectional area, and therefore, have a lower velocity. Theadvantage is that the flow meter can be shorter for the same flow raterange, and there will be a lower pressure drop. When there is nopressurized flow in the system, the enlarged head 300 of the piston 296rests on the tapered ribs of the flow guide 276.

The foregoing is illustrated by the following examples. In a firstexample, the frusto-conical portion of the flow guide has an inletdiameter of 1.25 in., an outlet diameter of 1.60 in., and an axiallength of 2.45 in. The enlarged head of the piston has a diameter of1.20 in., and the spring rate is 0.80 lb/in. In operation, the followingtable shows the enlarged head position from start of the frusto-conicalportion and the spring displacement for 5.0 gpm and 25.0 gpm flow rates.

Flow Rate Enlarged Head Position Spring Displacement (gpm) From Start(in.) (in.) 5.0 0.19 0.19 25.0 2.05 2.05

For a second example for comparison, a straight flow guide has adiameter of 1.25 in. The piston has a diameter of 1.20 in., and a springrate of 0.80 lbs/in. In operation, the following table shows the springdisplacement for 5.0 gpm and 25.0 gpm flow rates.

Flow Rate (gpm) Spring Displacement (in.) 5.0 0.19 25.0 4.78

The comparison of the spring displacements demonstrates that thefrusto-conical portion can be much shorter than a straight flow guide.For a flow rate of 25.0 gpm, the conical housing has a springdisplacement of 2.05 in. versus 4.78 in. for the straight housing.

The springs and shafts of the flow sensors can be made of metal, such asstainless steel. The other components of the flow sensors can be made ofplastic, such as acrylonitrile butadiene styrene (ABS), polymethylmethacrylate (PMMA), polypropylene (PP), and polyamides (PA). Inaddition to bolts and nuts, the housing components and the inlet andoutlet components can be glued or welded together.

With reference to FIG. 19, there is shown another flow sensor 410. Theflow sensor 410 can be embedded into a fluid system, such as anirrigation system. The flow sensor 410 includes an inlet 412, an outlet416, a body 415, and a flow meter 414.

As shown in FIG. 20, the inlet 412 and the outlet 416 are configured forattachment of the flow sensor 410 to conduits in an irrigation system.As illustrated, an inlet threaded collar 424 a connects an inlet fitting422 to the body 415 by threading onto exterior threading 418 a of thebody 415. An o-ring 421 a seats in an annular recess 417 in the inletfitting 422 and engages an inlet face 419 a to further seal the inletfitting 422 to the inlet face 419 a, and prevent water leakage at theinlet 412. The inlet fitting 422 has exterior threading 420 for beingthreaded into an interior threaded conduit end.

An outlet threaded collar 424 b connects an outlet fitting 426 to theflow sensor 410 by threading onto exterior threading 418 b of the body415. An o-ring 421 b seats in an annular recess (not shown) in theoutlet fitting 426 and further seals the outlet fitting 426 to an outletface 419 b of the outlet 416. The outlet fitting 426 has internalthreading 427 for cooperating with external threading on a downstreamconduit end. This configuration enables quick connection to conduits andmay accommodate different connections and conduit sizes.

As shown in FIGS. 20-22, the flow meter 414 includes an upper portion432 and a base portion 440. The upper portion 432 and the base portion440 form the body 415. The body 415 may be a single continuous piece,with the inlet 412 and the outlet 416 at opposite sides of the baseportion 440. The single piece body 415 requires fewer mechanical partsand is both easier to repair and to manufacture and assemble into theflow sensor 410. A top cover 428 includes radial tabs 430 that eachdefine a hole 436, which aligns with a corresponding hole 438 defined bya bore portion 434 of the upper portion 432. A threaded screw 442extends through each of the holes 436 of the radial tabs 430 and threadsinto the hole 438 of each of the bore portions 434 of the upper portion432.

The base portion 440 defines an inlet passage 444 and an outlet passage446. The inlet passage 444 is defined in part by an upward directedtubular portion 448 at the center of the base 440. The outlet passage446 extends around the tubular portion 448 and over a portion of theinlet passage 444 upstream of the tubular portion 448.

The upper portion 432 has an inward tapering configuration towards thebase 440. The upper portion 432 forms a lower chamber 450 and, incombination with the top cover 428, defines an upper chamber 452. Thelower chamber 450 houses a flow guide 454. The flow guide 454 includes atubular portion 456 followed by a frusto-conical portion 458.

As shown in FIGS. 23-25, the flow guide tubular portion 456 extends intothe inlet passage 444. The flow guide tubular portion 456 includestapered ridges 460. The tapered ridges 460 have a radially inward angledsurface 462 and a ledge 470. The tubular portion 456 has a slightlysmaller outer diameter than the inner diameter of the inlet passage 444so that the tubular portion 456 can slide inside the inlet passage 444,wherein a ledge recess 476 of the tubular portion 456 seats on teeth 466of the inlet passage 444. An annular bead 478 slides past the teeth 466and extends into an annular groove 480 at a base of the teeth 446,securing the flow guide 454 to the inlet passage 444.

The frusto-conical portion 458 of the flow guide 454 allows water toflow outward as it moves to the top of the upper chamber 452. Thefrusto-conical portion 458 may terminate with an upper edge 482 that iscurled outward and includes an outer surface that also turns downward toassist with a smooth transition for the flow from the flow guide 454down toward the outlet passage 446. For further assistance inredirecting the flow, the upper chamber 452 includes an arcuate, annularportion 484 (FIG. 21). The spacing between the outward flare and curledupper edge of the frusto-conical portion 458, on the one hand, and thesmooth curvature of the arcuate, annular portion 484 (FIG. 21) of theupper chamber 452, on the other hand, can be optimized so that pressuredrop is reduced through the flow sensor 410. For example, it has beenfound that reducing the spacing can minimize the pressure drop.

With reference to FIGS. 21 and 26, a piston 486 operates in the both thelower and upper chambers 450, 452 of the upper portion 432. The piston486 includes a shaft 488 with a hollow interior 500, a shaft head 506,and a plunger 499. The plunger 499 includes an enlarged head 490 with atubular portion 498 molded thereto. The enlarged head 490 operates inthe flow guide 454 and fits into the flow guide tubular portion 456 withsufficient clearance so that fluid can flow around the enlarged head 490to be more sensitive to low flow rates so that they can be measured whenthe enlarged head 490 is in the flow guide tubular portion 456. Thetubular portion 498 has an annular bead 492 that engages fingers 494 ofthe shaft 488. More specifically, the fingers 494 each have a groove 496that receives the annular bead 492 of the tubular portion 498 allowingthe shaft 488 to securely connect to the tubular portion 498 of theplunger 499.

When there is no flow, the enlarged head 490 seats on the ridge ledges470 of the tapered ridges 460 within the tubular portion 458 of the flowguide 454. The enlarged head 490 is centered in the flow guide 454 bytapered ribs 472 (FIG. 24). When water is flowing through the flow guide454, the tapered ribs 472 permit the piston 486 to move up and downlinearly with minimal friction between the enlarged head 490 and thetapered ridges 460.

In an alternative example shown in FIGS. 37-38, the flow sensor 410 maybe include a cylindrical flow guide 600. In this example, the flow guide600 has a cylindrical portion 602 that extends from a tubular portion608 and terminates with an upper edge 606. The tubular portion 608retains all of the same structure and functionality of the tubularportion 456 of the flow guide 410 as described above. The flow guide 600has straight (i.e., non-tapered) ribs 604 that center the enlarged head490 in the flow guide 600 and extend longitudinally along an inside wallof the flow guide 600. The ribs guide the piston 486 while moving up anddown linearly with minimum friction between the enlarged head 490 andthe tapered ridges 460.

The straight, cylindrical flow guide configuration is commonly moresensitive to flow rates than the frusto-conical flow guide. Thus, inorder to cover a range of flow rates as large as the flow guide 454, theflow guide 600 would need to be longer as discussed below. The straightguide can be substituted in each of the designs discussed herein for thefrusto-conical flow guide.

As the piston 486 moves upwards, the shaft 488 extends into a tubularportion 510 of an enclosure 502. More specifically, and as shown inFIGS. 26 and 27, the shaft head 506 has a rectangular hole 513 at thecenter of the shaft head 506. The rectangular hole 513 is of a slightlylarger size than the width of the twisted shaft 528. As the rate ofwater flow increases in the flow meter 414 forcing the piston 486upwards, the piston 486 will move up the twisted shaft 528, and thetwisted shaft 528 will move into the hollow interior 500 of the shaft488. As a result of this interaction, the twisted shaft 528 will convertthe linear motion of the shaft 458 into rotational motion of the twistedshaft 528.

With reference to FIGS. 21 and 32, a base portion 534 of the enclosure502 seats on a ledge 504 at the top of the upper portion 432. The baseportion 534 of the enclosure 502 has a series of recesses 505 to reducethe amount of plastic used in manufacturing. The enclosure 502 is housedin a cavity 538 of the top cover 428. The top cover 428 includes anannular bottom portion 429 that engages a top of the base portion 534 tomaintain the base portion 534 in place seated on the ledge 504. A seal526 provides a sealed engagement between the enclosure 502 and the upperportion 432 of the body 415. The seal 526 seats in an annular recessabout the base portion 534.

With reference to FIGS. 21 and 28, the enclosure 502 attaches to awasher 516. The washer 516 is disposed below the shaft head 506 aboutthe shaft 488. The washer 516 has a protrusion 520 that provides slightclearance between the washer 516 and the shaft head 506 for water toflow through holes 507 in the shaft head 506 and into the chamber 452.As shown in FIGS. 29-31, the tubular portion 510 of the enclosure 502has flexible fingers 514. Each flexible finger 514 can bend radiallyinward and outward. The flexible fingers 514 slide into holes 522 of thewasher 516, and each finger 514 has a lip 515 that clips to theunderside of a ledge 523 formed in the each of the holes 522 of thewasher 516 and snaps the enclosure 502 securely to the washer 516.

With reference to FIG. 32, the tubular portion 510 houses a helicalspring 518 and the twisted shaft 528 in the chamber 452. The shaft head506 has an annular pocket 509 for the helical spring 518 to seat in. Thetubular portion 510 also has ribs 530 (FIG. 31) that run longitudinallytherein. The ribs 530 provide enough clearance for the helical spring518, the shaft 488 and the washer 516 to move up and down linearly. Aswater flows up the inlet passage 444 and pushes on the piston 486, thepiston 486 is biased downward from the helical spring 518. The upwarddisplacement of the piston 486 depends on the rate of flow of the waterinto the inlet passage 444. A higher flow rate will push the shaft 488higher into the tubular portion 510 of the enclosure 502 than a lowerflow rate. If there is no water flow, the shaft 488 will not extend intothe tubular portion 510.

The top of the tubular portion 510 has an annular wall 511. The piston486 cannot rise vertically beyond the annular wall 511 in the chamber452. The outer diameter of the annular wall 511 is smaller than theinner diameter of the helical spring 518, and the inner diameter of thetubular portion 510 is larger than the outer diameter of the helicalspring 518. Therefore, as the piston 486 drives upward into the chamber452, the helical spring can coil up and collect around the annular wall511 and inside the tubular portion 510.

To prevent the piston 486 from rotating within the tubular portion 510of the enclosure 502, the shaft head 506 has a rib 508 (FIGS. 26 and 27)that slides vertically within a longitudinally running groove 512 (FIG.30) of the tubular portion 510.

The tubular portion 510 terminates at a top portion 536 (FIG. 21) of thetop cover 428. Both the tubular portion 510 and the top portion 536 havea hole (532 of FIG. 30 and 540 of FIG. 22, respectively), that alignwith one another. With reference to FIGS. 33-35, the holes 532, 540permit a spindle 542 to connect the twisted shaft 528 to a dial arrow552 of a dial assembly 544. The spindle 542 has ridges 543 runninglongitudinally along an upper portion 547 and a lower portion 549. Theend of the lower portion 549 fits in the hole 532 of a boss 529 (FIG.27) of the twisted shaft 528, and the ridges 543 penetrate the surfaceof the boss 522 forming the hole 532 to prevent rotation of the spindle542 within the hole 532. The boss 529 also has a series of recesses 531to reduce the amount of plastic used in manufacturing. A tubular tip 554extending from a base position 561 of the dial arrow 552 pivots in adome-shaped recess 556 of the dial cover 550. The end of the upperportion 547 of the spindle 542 has a conical tip 551 that isaccommodated by the tubular tip 554. The ridges 543 penetrate into theinner surface of the tubular tip 551 to secure the dial arrow 552 to thespindle 542 and prevent rotation of the spindle 542 within the tubulartip 554 of the dial arrow 552. Therefore, as the spindle 542 rotates dueto the rotation of the twisted shaft 528, the dial arrow 552 rotates atthe same rate as the spindle 542.

With reference to FIG. 34, a retention clip 553 seats in-between adome-shaped portion 503 (FIG. 29) of the enclosure 502 and the topportion 536 of the top cover 428. The retention clip 553 is fastenedaround a groove 545 of an intermediate portion 559 of the spindle 542 toprevent axial movement of the spindle 542. The retention clip 553 has aC-shaped split ring configuration. The dome-shaped portion 503 houses anannular seal 555. The seal 555 has redundant wipers 557 that wrap aroundand engage the spindle 542 to prevent water from exiting the enclosure502 through the hole 532 of the tubular portion 510.

Referring to FIG. 35, the dial assembly 544 also includes a dial 546, ahelical spring 548, and a transparent dial cover 550. The twisted shaft528, the spindle 542 and the dial arrow 552 are splined together suchthat they rotate together. The twist in the twisted shaft 528 turns thetwisted shaft 528, the spindle 542 and the dial arrow 552 as the shaft487 extends higher into the tubular portion 510 of the enclosure 502 aswater flow increases through the flow meter 414.

The dial 546 has tabs 558 that seat in complimenting grooves 560 (FIG.22) of the top cover 428 to prevent the dial 546 from rotating. Thehelical spring 548 separates the dial 546 and the dial cover 550 topermit the dial arrow 552 to rotate. The dial 546 may be marked withindicia or indicators for the amount of water flow through the flowmeter 414. For instance, the dial 546 may have indicia indicating ascale for water flow in gallons per minute and/or liters per minute. Asthe flow rate increases, the dial arrow 552 will rotate in a clockwisefashion as viewed from above the flow sensor 410.

The dial cover 550 can have color coded sections that designate flowrate ranges. For example, if the flow through a particular system is 10gpm, a user will use the dial cover 550 to indicate this flow rate of 10gpm. To do so, a user may remove the screw 564 of the threaded collar562, and unthread the threaded collar 562 a few turns. This clearancewill allow the helical spring 548 to lift the dial cover 550 off of thetop cover 428, allowing a user to rotate the dial cover 550. The dialcover 550 has detents 569 at the perimeter that extend from its inwardface that seat in incremental pockets 541 (FIG. 36) of the top cover428. Thus, the user can rotate the dial cover 550 to center a first flowrate indicator section 567 over a marking 570 on the dial 546 indicating10 gpm. The first flow rate indicator section 567 represents anacceptable range of rate of flow. The first flow rate indicator section567 may have a semitransparent color (such as semitransparent green).The semitransparent color permits the user to still be able to visuallyobserve the dial arrow 552 and the markings 570 on the dial 546 beneaththe dial cover 550. The user may then align the detents 569 with theappropriate pockets 541, thread the threaded collar 562 back on to thetop cover 428 to lock the detents 569 in the underlying pockets 541, andfurther secure the threaded collar 562 with the screw 564.

The dial cover 550 may also have a second, outer flow rate indicatorsection 568 that is a different semitransparent color (such assemitransparent yellow) and straddles the first, inner flow rateindicator section 567. The outer flow rate indicator section 568indicates that the flow rate through the flow sensor 410 has eitherincreased or decreased by some percentage beyond the normal gpm range asindicated by the first, inner flow rate indicator section 567.

Finally, as shown in FIG. 22, a threaded collar 562 threads on to thetop cover 428 to secure the dial assembly 544 in place. The threadedcollar 562 has a hole 566 to accommodate a set screw 564 to pass throughand bite into the top cover 428 to prevent unintentional removal of thethreaded collar 562 and further secure the threaded collar 562 to thetop cover 428. The set screw 564 has a non-traditional tool socket(e.g., a hex tool socket) to aid in prevention of vandalism orunintentional removal. Additionally, the threaded collar 562 could havethe transparent dial cover 550 affixed to it.

In operation, fluid flows into the flow sensor 410 through the inletpassage 444. As the flow increases, the fluid moves the piston 486upwards in the lower and upper chambers 450, 452. The piston 486 causesthe dial assembly 544 to determine the flow rate through the flow sensor410. That is, the upward movement of the piston 486 against the helicalspring 518 causes the twisted shaft 528 to turn and twist in the chamber452. The twisting of the twisted shaft 528 converts linear motion of thepiston 486 to rotational motion, and rotates the dial arrow 552 aboutthe dial 546 indicating the flow through the flow meter 414 of the flowsensor 410. As the flow meter 414 is measuring the flow, the fluid flowsaround the enlarged head 490 of the piston 486 and through the flowguide 454. Then, the flow is guided by the accurate, annular portion 484of the upper portion 432 and the curled edge 482 of the flow guide 454to turn the direction of flow back towards the outlet passage 446.

The piston 486, the spring 528 and the frusto-conical portion 458 of theflow guide 454 are coordinated to measure flow through flow meter 414.The tubular portion 456 may also be part of this coordination. Since theenlarged head 490 of the piston 486 has a constant diameter, the radialdistance between a perimeter of the enlarged head 486 and thefrusto-conical portion 458 of the flow guide 454 increases as the piston486 rises. This enables the flow meter 414 to have a reduced overalllength (or height) when compared to a constant diameter flow guide. Morespecifically, in general, higher velocities mean a higher force on theenlarged head 490 of the piston 486. For an expanding area, such as thatprovided by the frusto-conical portion 458 of the flow guide 454, thevelocity will decrease over the length for a given flow rate. So, athigher flow rates, the enlarged head 490 will be located in a section ofthe frusto-conical portion 458 with a larger cross-sectional area and,therefore, have a lower velocity. The advantage is that the flow metercan be shorter for the same flow rate range, and there will be a lowerpressure drop. When there is no pressurized flow in the system, theenlarged head 490 of the piston 486 rests on the tapered ribs 472 of theflow guide 454. The flow sensor 410 can measure small amounts of flowdownstream of a valve, which may indicate a leak in the valve. The flowsensor 410 also can measure above normal flows, which may indicatedamaged connections, conduit or water emission devices downstream. Italso could measure below normal flow amounts which may indicate cloggedconduit or water emission devices.

The foregoing is illustrated by the following examples. In a firstexample, the flow sensor has an inlet of 1 in. and a flow guide with aninlet diameter of 1.25 in., an outlet diameter of 1.75 in., and an axiallength of 2.396 in., as measured from the top of the ledges of thetubular portion to the upper edge of the frusto-conical portion. Thestraight/tubular portion of the flow guide has an axial length of 0.718in., and the frusto-conical portion of the flow guide has an axiallength of 1.678 in. and proceeds outward at an angle of 8.62°. Theenlarged head of the piston has a diameter of 1.21 in., and there is agap of 0.04 in. between the enlarged head and the tapered ribs, whichrun along the wall of the flow guide. The tapered ribs are designed tocreate a linear path for the piston to travel. Furthermore, the gapbetween the wall of the flow guide and the enlarged head increases asthe piston travels away from the straight portion of the flow guide andthrough the frusto-conical portion of the flow guide.

The twisted shaft is 2.5 in. in length, and the pitch is 1.84revolutions per inch (“rev/in”). The spring rate is 0.66 lb/in. In apreferred embodiment, with the foregoing dimensions and conditions, theangle in degrees for the markings on the dial indicate a given flow rateare shown in the table below.

Flow Rate (gpm) Angle (degrees) 0.0 0 0.5 23 5.0 160 10.0 215 15.0 26020.0 304 25.0 342

In operation, the following table shows the enlarged head position fromstart of the ledges of the straight portion of the flow guide and thespring displacement for 5.0 gpm and 25.0 gpm flow rates.

Flow Rate Enlarged Head Position Spring Displacement (gpm) From Start(in.) (in.) 5.0 .7522 .7522 25.0 1.760 1.760

In a second example, the flow sensor has an inlet of 1.5 in., and theflow guide has an inlet diameter of 1.75 in., an outlet diameter of 2.3in., and an axial length of 2.937 in., as measured from the top of theledges of the tubular portion to the upper edge of the frusto-conicalportion. The straight portion of the flow guide has an axial length of0.960 in., and the frusto-conical portion has an axial height of 1.977in. and proceeds outward at an angle of 8.14°. The enlarged head of thepiston has a diameter of 1.600 in., and there is a gap of 0.05 in.between the enlarged head and the tapered ribs. The tapered ribs aredesigned to create a linear path for the piston to travel. Furthermore,the gap between the wall of the flow guide and the enlarged headincreases as the piston travels away from the straight portion of theflow guide through the frusto-conical portion of the flow guide.

The twisted shaft is 3.15 in. in length, and the pitch of the twistedshaft is 2.60 rev/in. The spring rate is 2.5 lb/in. In a preferredembodiment, with the foregoing dimensions and conditions, the angle indegrees for the markings on the dial indicating a given flow rate areshown in the table below.

Flow Rate (gpm) Angle (degrees) 0.0 0 15 140 30 215 45 266 60 315 70 350

In operation, the following table shows the enlarged head position fromthe ledges of the straight portion and the spring displacement for 15.0gpm and 70.0 gpm flow rates.

Flow Rate Enlarged Head Position Spring Displacement (gpm) From Start(in.) (in.) 15.0 1.01 1.01 70.0 2.52 2.52

As discussed in a previous example, a straight housing flow guide with a1.25 in. inlet diameter and a spring rate of 0.80 lbs/in. had springdisplacements of 0.19 in. and 4.78 in. for flow rates of 5.0 gpm and25.0 gpm, respectively. The straight housing flow guide has asignificantly larger displacement than the frusto-conical flow guideexamples, as described above.

The foregoing dimensions and conditions are exemplary only. Thedimensions and conditions and be changed to accommodate measuring largeror smaller flows.

As with previous embodiments, the helical springs and shafts of the flowsensors can be made of metal, such as stainless steel. The othercomponents of the flow sensors can be made of plastic, such asacrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA),polypropylene (PP), and polyamides (PA).

With reference to FIG. 39, there is shown another flow sensor 710. Theflow sensor 710 can be embedded into a fluid system, such as anirrigation system. The flow sensor 710 includes an inlet 712, an outlet716, a pressure regulator 713, a body 715 and a flow meter 714. Someelements may be the same as those presented in previous embodiments andwill retain the same reference numbers for clarity. This embodimentincludes a combined filter and flow guide. Therefore, it may also beused, along with a dial and a plunger cap assembly, to easily retrofitexisting filter assemblies to be both a filter and flow sensors. Inthese retrofitted instances the body of the filter assembly is leftinstalled in the irrigation system and reused.

The inlet 712 and the outlet 716 are configured for attachment of theflow sensor 710 to conduits in an irrigation system. The inlet 712 hasexterior threading 720 for being threaded into an interior threadedconduit end. The outlet 716 also has exterior threading 727 forcooperating with interior threading on a downstream conduit end. Insteadof threading, other attachment methods may be used, such as gluing,clamping or welding.

With reference to FIGS. 39 and 40, the flow meter 714 includes an upperportion 732 and a base portion 740. The upper portion 732 and the baseportion 740 form the body 715. The body 715 may be a single continuouspiece, with the inlet 712 and the outlet 716 at opposite sides of thebase portion 740. The single piece body 715 requires fewer mechanicalparts and is both easier to repair and to manufacture and assemble intothe flow sensor 710. A top cover 728 has internal threading 729 forthreading onto external threading 731 of the upper portion 732.

The base portion 740 defines an inlet passage 744 and an outlet passage746. The inlet passage 744 is defined in part by an upward directedtubular portion 748 at the center of the base 740. The outlet passage746 extends around the tubular portion 748 and over a portion of theinlet passage 744 upstream of the tubular portion 748.

The upper portion 732 may be cylindrical in shape and has a verticalconfiguration relative to the base 740. The body 715 forms a lowerchamber 750, and the top cover 728 defines an upper chamber 752. Thelower chamber 750 houses a filter 753 and a flow guide 754. The filter753 and the flow guide 754 form a single piece flow guide/filter body755 (e.g., FIG. 42).

As shown in FIG. 43, the flow guide 754 includes a tubular lower portion756 with walls 745 that taper slightly inwards from a base 779 of theflow guide 754 to a middle portion 781 of the flow guide 754. The flowguide 754 also includes a tubular upper portion 758 with an annularinner wall 757 that taper inwards from an upper edge 782 down to atransition 781 to the tubular lower portion 756 of the flow guide 754.The rate of taper of the tubular lower portion 756 is smaller than therate of taper of the tubular upper portion 758. More specifically, therate of taper of tubular lower portion 756 can be relatively negligiblefor the function of the flow meter 714 and can be determined merely toaccommodate the molding process. The rate of taper for the tubular upperportion 758 can be set at any desired angle; however, it is generallybounded by the radial and vertical space available in the portion of thechamber 750 inside of the filter 753 and the diameter of the enlargedhead 490. The function of the tubular upper portion 758 can be mainlycontrolled by the spring constant of the spring 518 as opposed to therate of taper.

The tubular lower portion 756 has a slightly larger inner diameter thanthe outer diameter of the upwardly directed tubular portion 748 of theinlet passage 744 so that the tubular portion 756 can slide on to theoutside of the tubular portion 748 with a friction fit that forms aseal. The transition 781 includes a chamfered surface 806 and a steppedsurface 776 that engage complimentary surfaces on the terminal end 766of the tubular portion 748 of the inlet passage 744.

With reference to FIGS. 42 and 43, the flow guide/filter body 755 may bemolded as a single piece or it may be assembled with multiplecomponents. For example, the flow guide may be a separate componentaffixed to the filter body. The flow guide/filter body 755 includes anannular base 787 of the filter 753. The annular base 787 defines slots788 configured to receive tooling to hold the mesh screen 794 during themolding process. A portion of the annular base 787 seats on a ledge 745(FIG. 41) of the inlet passage 744 and terminal ends of ribs 805 (seeFIG. 44) that extend radially inward from the upper portion 732 near thebase portion 740 (see FIG. 44). The filter 753 has supports 789extending longitudinally from the annular base 787 to an annular top 791of the filter 753. The supports 789 may be equally spaced from oneanother about the diameter of the annular base 787. The supports 789 maytake on a rectangular cross-sectional shape or some other shape, such asa cylindrical, triangular or a trapezoidal cross-section. The top 791also has a lower ring 795. An upper ring 797 is on top of the lower ring795. The upper ring 797 has a larger outer diameter than the lower ring795. The upper ring 797 defines notches 793 equally spaced about thediameter of the upper ring 797.

A mesh screen 794 could be fixed inside the filter body 753 to the lowerring 795, the annular base 787 and the filter support elements 789. Forexample, the mesh screen 794 could be over-molded onto the lower ring795, the annular base 787 and the filter support elements 789. The meshscreen 794 filters debris from the water flowing through the filter.Alternatively, the mesh screen 794 could be a cylinder that slides intothe filter body 753. Also, the mesh screen 794 could be mounted to theoutside of the filter body 753.

The upper ring 797 includes a flange 801 so that the flow guide/filterbody 755 seats on an annular recess ledge 799 (FIG. 41) of the upperportion 732 of the flow body 715. With reference to FIG. 42, tabs 803extend radially from the annular base 787 and fit in-between the ribs805 to prevent rotation of the flow guide/filter body 755.

The annular inner wall 757 of the tubular upper portion 758 of the flowguide 754 allows water to flow outward as it moves to the top of theupper chamber 752. Water will flow past the upper edge 782 into thelower chamber 750 and down toward the outlet passage 746. For furtherassistance in redirecting the flow, the upper chamber 752 includes anarcuate, annular portion 784 (FIG. 39).

In a manner similar to previous embodiments, and with reference to FIGS.39 and 40, the piston 486 operates in the both the lower and upperchambers 750, 752 of the upper portion 732. The piston 486 includes theshaft 488 with the hollow interior 500, the shaft head 506, and theplunger 499 of the top cover 728. The plunger 499 includes the enlargedhead 490 with the tubular portion 498 fixed thereto. The enlarged head490 operates in the flow guide 754 and fits into the tubular portion 748of the inlet passage 744 with a slight clearance so that fluid can flowaround the enlarged head 490 to be more sensitive to low flow rates sothat they can be measured when the enlarged head 490 is in the tubularportion 498 overlapped with the tubular portion 756. The clearancebetween the enlarged head 490 and the inside diameter of the tubularportion 748 is preferably approximately 0.020 inches. As shown in FIGS.26 and 27, the annular bead 492 of the tubular portion 498 engages thefingers 494 of the shaft 488. More specifically, the fingers 494 eachhave grooves 496 that receive the annular bead 492 of the tubularportion 498 allowing the shaft 488 to securely connect to the tubularportion 498 of the plunger 499. Alternatively, the fingers could extendfrom the tubular portion and the annular bead could be about shaft.

With reference to FIGS. 45 and 46, a tubular portion 810 of the topcover 728 forming the upper chamber 752 attaches to a washer 816. Thewasher 816 is disposed below the shaft head 506 about the shaft 488.When there is no flow, the shaft head seats on the washer 816. Thewasher 816 has a series of recesses 827 to reduce the amount of materialused in manufacturing. As shown in FIGS. 45-48, the tubular portion 810of the top cover 728 has flexible fingers 814. Each flexible finger 814can bend radially inward and outward. Each flexible fingers 814 has alip 815 that clips to the underside of a ledge 823 formed by an annularrecess 825 of the washer 816 and snaps the tubular portion 810 securelyto the washer 816.

The enlarged head 490 is centered in the flow guide 454 by a wall 745 ofthe tubular portion 748 of the inlet passage 744. When water is flowingthrough the flow guide 754, the wall 745 of the tubular portion 748permits the piston 486 to move up and down linearly with minimalfriction between the enlarged head 490 and the wall 745.

As the piston 486 moves upward, the shaft 488 extends into the tubularportion 810 of the top cover 728, as shown in FIGS. 39 and 46. Morespecifically, the present embodiment may have the same shaft head 506with the rectangular hole 513 at the center of the shaft head 506 asshown in FIGS. 26 and 27. The rectangular hole 513 make take on someother shape, such as a square or a triangle. The rectangular hole 513 isof a slightly larger size than the cross-sectional dimensions of thetwisted shaft 528. The cross-sectional shape can have the same shape asthe hole 513. That is, with a square shaped hole, the twisted shaftcould have a square shaped cross-sectional shape. The samecorrespondence could be done for the other shapes. As the rate of waterflow increases in the flow meter 714, the piston 486 will move up thetwisted shaft 528, and the twisted shaft 528 will move into the hollowinterior 500 of the shaft 488. As a result of this interaction, thetwisted shaft 528 will convert the linear motion of the shaft 488 intorotational motion of the twisted shaft 528.

The tubular portion 810 houses the helical spring 518 and the twistedshaft 528 in the chamber 752. The tubular portion 810 also has ribs 830(FIG. 47) that run longitudinally therein. The ribs 830 provide asmaller surface that, in turn, reduces friction so that the helicalspring 518, the shaft 488 and the shaft head 506 move freely up and downlinearly, but are maintained in a linear operating configuration. Thisensures that the plunger 499 remains centrally located in the flow guide754 and the tubular portion 748 of the inlet passage 744. As water flowsup the inlet passage 744 and pushes on the piston 486, the piston 486 isbiased downward from the helical spring 518. The upward displacement ofthe piston 486 depends on the rate of flow of the water into the inletpassage 744. A higher flow rate will push the shaft 488 higher into thetubular portion 810 of the top cover 728 than a lower flow rate. Ifthere is no water flow, the shaft 488 will not extend into the tubularportion 810. The tubular upper portion 758 may include longitudinallyextending ribs 761 that are wedged shaped and that engage and guide theenlarged head 490 as it reciprocates. It also provides clearance for thewater to pass around the enlarged head 490 and low friction surfaces forthe enlarged head 490 to move on as it reciprocates.

The rate of flow through the inlet passage may be sufficient enough toupwardly force the enlarged head 490 of the piston 486 to move in theflow guide tubular upper portion 758. Despite the inner diameter of thetubular upper portion 758 being larger than the diameter of the enlargedhead 490 at any point within the tubular upper portion 758, the pistonwill still be guided to move vertically (and not laterally) since theshaft head 506 is centered in the tubular portion 810 by the ribs 830 ofthe tubular portion 810.

The top of the tubular portion 810 has an annular wall 811 extendinglongitudinally into the chamber 752. The piston 486 cannot risevertically beyond the annular wall 811. The outer diameter of theannular wall 811 is smaller than the inner diameter of the helicalspring 518, and the inner diameter of the tubular portion 810 is largerthan the outer diameter of the helical spring 518. Therefore, as thepiston 486 drives upward into the chamber 752, the helical spring 518can coil up and collect around the annular wall 811 and inside thetubular portion 810.

To prevent the piston 486 from rotating within the tubular portion 810of the top cover 728, the rib 508 (FIGS. 26 and 27) of the shaft head506 slides vertically within a longitudinally running groove 812 (FIG.48) of the tubular portion 810.

With reference to FIGS. 46, 48, and 49, the tubular portion 810terminates at a top portion 836 of the top cover 728. The top portion836 defines a hole 832 that permits the spindle 542 to connect thetwisted shaft 528 to a dial pointer 852 of a dial assembly 844. Asdescribed in a previous embodiment (see FIGS. 33-34), and with referenceto FIGS. 46 and 49, the spindle 542 has ridges 543 runninglongitudinally along the upper portion 547 and the lower portion 549.The end of the lower portion 549 fits in the hole 832 of the boss 529 ofthe twisted shaft 528 with a friction fit, and the ridges 543 penetratethe surface of the boss 529 forming the hole 832 to prevent rotation ofthe spindle 542 within the hole 832. The boss 529 also has a series ofrecesses 531 to reduce the amount of material used in manufacturing. Theupper portion 547 of the spindle 542 has a conical tip 551 that isaccommodated by the tubular tip 554. The connection is a friction fit.The ridges 543 penetrate into the inner surface of the tubular tip 554to secure the dial pointer 852 to the spindle 542 and prevent rotationof the spindle 542 within the tubular tip 554 of the dial pointer 852.Therefore, as the spindle 542 rotates due to the rotation of the twistedshaft 528, the dial pointer 852 rotates at the same rate as the spindle542.

In a similar manner as described in a previous embodiment, the retentionclip 553 seats in-between the dome-shaped portion 503 (see e.g., FIG.29) of the top cover 728. The retention clip 553 is fastened around thegroove 545 of the intermediate portion 559 of the spindle 542 to preventaxial movement of the spindle 542. The retention clip 553 has a C-shapedsplit ring configuration. The spindle has washers 851 (FIG. 40) thatseat above and below the retention clip 553. The dome-shaped portion 503houses the annular seal 555 (FIG. 34). The seal 555 has redundant wipers557 that wrap around and engage the spindle 542 to prevent water fromexiting the enclosure 502 through the hole 832 of the top cover 728.

Referring to FIG. 49, the dial assembly 844 also includes a dial 846 anda transparent dial cover 850. The twisted shaft 528, the spindle 542 andthe dial pointer 852 are splined together such that they rotatetogether. The twist in the twisted shaft 528 turns the twisted shaft528, the spindle 542 and the dial pointer 852 as the shaft 487 extendshigher into the tubular portion 810 of the top cover 728 as water flowincreases through the flow meter 714.

The dial 846 has tabs 858 that seat in complimenting grooves 870 of adial seat 859 to prevent the dial 846 from rotating. The dial 846 may bemarked with indicia or indicators 883 for the amount of water flowthrough the flow meter 714. For instance, the dial 846 may have indicia883 indicating a scale for water flow in gallons per minute and/orliters per minute. As the flow rate increases, the dial pointer 852 willrotate in a clockwise fashion as viewed from above the flow sensor 710.

With reference to FIGS. 51 and 52, the dial seat 859 has a recess 860that receives a protrusion 855 of the top cover 728 which prevents thedial seat from rotating as the spindle 542 rotates inside a hole 862 ofthe dial seat 859. The dial seat 859 seats on top of the top cover 728and is further secured to the top cover 728 with set screws 871 (FIG.49). The set screw 871 has a non-traditional tool socket (e.g., a hextool socket) to aid in prevention of vandalism or unintentional removal.Each set screw 871 pass through holes 861 of the dial seat 859 and maybe threaded into holes 853 of bosses 887 of the top cover 728. The topcover 728 has series of recesses 857 to reduce the amount of materialused in manufacturing.

With reference to FIGS. 50 and 53, a flow rate gauge 880 connects to thedial assembly 844 and the top cover 728. The flow rate gauge 880 has asemi-annular recess 882 that accommodates the dial seat 859 and allowsthe flow rate gauge 880 to slide around the perimeter of the dialassembly 844. As the flow rate increases, the dial pointer 852 willrotate in a clockwise fashion as viewed from above the flow sensor 710.The flow rate gauge 880 indicates whether the flow rate through the flowsensor 710 is within the normal gpm range or has either increased ordecreased by some amount beyond the normal gpm range. For example, if anormal flow through a particular system is 10 gpm, a user will move theflow rate gauge 880 to indicate this flow rate of 10 gpm.

The flow rate gauge 880 can have color coded sections that designateflow rate ranges. For example, an inner section 884 may be greenindicating normal flow, and outer sections 885 that straddle the innersection 884 may have other colors (e.g., yellow and red) indicatingundesirable flow ranges. The transparent dial cover 850 permits the userto still be able to visually observe the dial pointer 852 and themarkings 883 on the dial 846.

The dial 846 also starts with smaller intervals, such as 0, 1, 2, 5 gpmand transitions to longer intervals, such as 10 and 20 gpm. The abilityto have this setup is provided by the flow guide 754 first having alower cylindrical portion and then an upper frusto-conical portion.

With reference to FIG. 54 and FIG. 56, there is shown an alternative topcover 928, flow gauge 980 and dial assembly 944. The top cover 928 has atubular portion 910, an annular ledge 961 and an annular top ring 963.The tubular portion 910 has ribs 930 (FIG. 57) that run longitudinallytherein. The ribs 930 provide a smaller surface that, in turn, reducesfriction so that the helical spring 518, the shaft 488 and the shafthead 506 move freely up and down linearly, but are maintained in alinear operating configuration. To prevent the piston 486 from rotatingwithin the tubular portion 910 of the top cover 928, the rib 508 (FIGS.26 and 27) of the shaft head 506 slides vertically within alongitudinally running groove 912 (FIG. 57) of the tubular portion 910.

The dial assembly 944 includes a dial 946 and a transparent dial cover950. As with previous embodiments, the twisted shaft 528, the spindle542 and the dial pointer 852 are splined together such that they rotatetogether. The twist in the twisted shaft 528 turns the twisted shaft528, the spindle 542 and the dial pointer 852 as the shaft 487reciprocates in the tubular portion 810 of the top cover 928 as waterflow increases and decreases through the flow meter 714.

The transparent dial cover 950 snap fits on to a top cover body 934.More specifically, an o-ring 995 seats in an annular recess 959 of thebody 934, and the transparent dial cover 950 includes an inner annularrecess 931 complimentary in shape to the o-ring 995. The transparentdial cover 950 can slide over the o-ring 995 and snap fit securely tothe top cover body 934.

The dial 946 has radial tabs 958 that seat in complementary radialgrooves 960 of the top ring 963 of the top cover 928 to prevent the dial946 from rotating. The dial 946 may be marked with indicia or indicators933 for the amount of water flow through the flow meter 714. Forinstance, the dial 946 may have indicia 933 indicating a scale for waterflow in gallons per minute (gpm) and/or liters per minute. As the flowrate increases, the dial pointer 852 will rotate in a clockwisedirection as viewed from above the flow sensor 710, and as the flow ratedecreases, the dial pointer 852 will rotate in a counter-clockwisedirection as viewed from above the flow sensor 710.

With reference to FIGS. 55, 56, and 57, when the top cover 928 and thedial assembly 944 are in an assembled configuration, the flow rate gauge980 clamps to the dial assembly 944 and the top cover 928. Thetransparent dial cover 950 has an annular flange 951 about its perimeterthat engages the annular ledge 961 of the top cover 928. The flow rategauge 980 has an indicator portion 981 and a base portion 982, whereinthe flange 951 of the dial cover 950 and the ledge recess 961 of the topcover 928 are sandwiched between the indicator portion 981 and the baseportion 982. Specifically, the ledge recess 951 seats on a lower seat923 of the base portion 982 of the flow rate gauge 980. A bottom surface924 of the indicator portion 981 seats on an outer seat 920 of the baseportion 982. The flange 951 sits on the inner seat 927, the outer seat920 and the rail 921. The flange 952 includes an annular groove 932 thatreceives the complimentary shaped rail 921 of the base portion 982 toguide the flow rate gauge 980 about the perimeter of the dial assemblyand further assists preventing the flow rate gauge 980 fromunintentionally releasing from the dial assembly 944.

The indicator portion 981 and the base portion 982 clamp the dial cover950 and the top cover 928 with a screw 983. The screw 983 has anon-traditional tool socket (e.g., a hex tool socket). The screw 983passes through a hole 991 of a first boss 992 of the indicator portion981 and then a hole 926 of a second boss 993 of the base portion 982. Aspring washer 987 sits in a spring washer recess 925 about the hole 926.The hole 926 can be pre-threaded or self-threaded on the initialinstillation of the screw 983. The indicator portion 981 defines apartially cylindrical recess 997 to accommodate the head of the screw883. The spring washer 987 maintains tension on the screw 983 so thatthe indicator portion 981 and the base portion 982 do notunintentionally loosen from one another.

The screw 983 may be loosened to manually slide the flow rate gauge 880around the perimeter of the dial assembly 944. The indicator portion 981extends upward so not to contact the dial cover 950 as the flow rategauge 980 is moved about the perimeter of the dial cover 950. As theflow rate changes, the dial pointer 852 will rotate. The flow rate gauge980 indicates whether the flow rate through the flow sensor 710 iswithin the normal gpm range defined on the indicator portion 981 or haseither increased or decreased by some amount beyond the normal gpmrange.

More specifically, if a normal flow through a system is 10 gpm, a userwill move the flow rate gauge 980 to indicate this flow rate of 10 gpmas the normal operating flow for the system. The flow rate gauge 980 canhave color coded sections that designate flow rate ranges. For example,an inner section 984 may be green indicating normal flow, and outersections 985 that straddle the inner section 884 may have other colors(e.g., yellow and red) indicating undesirable flow ranges. Thetransparent dial cover 950 permits the user to visually observe the dialpointer 852 and markings 983 on the dial 946.

In some cases, if the flow rate is observed to decrease from irrigationcycle to irrigation cycle, this may indicate that the filter 783 may begetting clogged with debris. For example, if the normal flow ratethrough the flow sensor 710 is 20 gpm and the flow rate has dropped to16 gpm over a period time (e.g., a few days) this may be an indicationthat debris in the filter 783 is inhibiting water to pass through thefilter 783 and flow downstream.

In operation, fluid flows into the flow sensor 710 through the inletpassage 744. As the flow increases, the fluid moves the piston 486upwards in the lower and upper chambers 750, 752. The piston 486 causesthe dial assembly 844 to determine the flow rate through the flow sensor710. That is, the upward movement of the piston 486 against the helicalspring 518 causes the twisted shaft 528 to turn and twist in the chamber752. The twisting of the twisted shaft 528 converts linear motion of thepiston 486 to rotational motion, and rotates the dial pointer 852 aboutthe dial 846 indicating the flow through the flow meter 714 of the flowsensor 710. As the flow meter 714 is measuring the flow, the fluid flowsaround the enlarged head 490 of the piston 486 and through the flowguide 754. Then, the flow is guided by the accurate, annular portion 784of the upper portion 732 of the flow guide 754 to turn the direction offlow back towards the outlet passage 746. The flow passes through themesh screen 794 of the filter 753 to flow to the outlet passage 746.

The piston 486, the spring 518, the twisted shaft 528 and the flow guide754 are coordinated to measure flow through flow meter 714. Since theenlarged head 490 of the piston 486 has a constant diameter, the radialdistance between a perimeter of the enlarged head 486 and the uppertubular portion 758 of the flow guide 754 increases as the piston 486rises. This enables the flow meter 714 to have a reduced overall length(or height) when compared to a constant diameter flow guide. Morespecifically, in general, higher velocities mean a higher force on theenlarged head 490 of the piston 486. For an expanding area, such as thatprovided by the conical tapered wall 758 of the upper tubular portion758 of the flow guide 754, the velocity will decrease over the lengthfor a given flow rate. So, at higher flow rates, the enlarged head 490will be located in a section of the upper tubular portion 758 with alarger cross-sectional area and, therefore, have a lower velocity. Theadvantage is that the flow meter can be shorter for the same flow raterange, and there will be a lower pressure drop.

Additionally, the combined flow guide/filter body 755 formed by theintegration of the flow guide 754 into the filter 753 allows for thesimple manufacturing of a flow guide system coupled with a filter toprevent clogging and damage to the irrigation system. It also providesthe ability to retrofit existing filter bodies to become both a filterand a flow sensor. One can simply do this by removing the filter top andthe filter. Then, the combined filter and flow guide is inserted intothe body. The filter cap is replaced with a new cap assembly thatincludes the dial assembly 844 (or with the dial assembly 944 and topcover 928), the piston 486, the top cover 728, the twisted shaft 528,the washer 816 and the helical spring 518 all assembled as a singleunit,

The flow sensor 710 can measure small amounts of flow downstream of avalve, which may indicate a leak in the valve. The flow sensor 710 alsocan measure above normal flows, which may indicate damaged connections,conduit or water emission devices downstream. It also could measurebelow normal flow amounts which may indicate clogged conduit or wateremission devices.

As with previous embodiments, the helical springs and shafts of the flowsensors can be made of metal, such as stainless steel. The othercomponents of the flow sensors can be made of plastic, such asacrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA),polypropylene (PP), and polyamides (PA).

Dimensions and flow rates may be similar to previous embodiments and areonly exemplary. The dimensions and conditions can be changed toaccommodate measuring larger or smaller flows. For example, to target asmaller maximum flow rate (e.g., set the maximum flow rate to 10 gpmfrom 20 gpm), the flow sensor can be fitted with a lighter spring (i.e.,a lower spring constant). This device will perform in a similar fashionas the previous designs. This version has been scaled down toaccommodate a smaller package so to be able to also be able to fit intoexisting filter bodies. The target is 0 to 20 gpm instead of 0 to 25gpm. The lower range is due to the smaller size of the body, and in someinstances, there is a recommended flow rate for filters of 20 gpm. Itshould also be further understood that the flow range of the unit can betuned to any desired range by changing the spring rate. If a smallerrange (0 to 10 gpm) is desired, then a lighter spring (lower springconstant spring) is used to obtain the same travel, bothlinearly/rotationally, of the pointer or arrow. This version can also bescaled as desired to accommodate higher and lower flow rates.

The matter set forth in the foregoing description and accompanyingdrawings is offered by way of illustration only and not as a limitation.While particular embodiments have been shown and described, it will beapparent to those skilled in the art that changes and modifications maybe made without departing from the broader aspects of the technologicalcontribution. The actual scope of the protection sought is intended tobe defined in the following claims.

What is claimed is:
 1. A flow sensor comprising: a body; a combined flowguide and particulate filter unit associated with the body and includingat least a hollow frusto-conical portion; a piston operating inside atleast a portion of the hollow frusto-conical portion of the combinedflow guide and filter unit based on an amount of fluid flowing throughthe flow sensor; and a flow indicator assembly to indicate the flowthrough the flow sensor based on movement of the piston in the combinedflow guide and filter unit.
 2. The flow sensor of claim 1 wherein thecombined flow guide and filter is attached to an inlet passage portionof the body.
 3. The flow sensor of claim 2 wherein the piston operatesin association with the inlet passage portion and the combined flowguide and filter unit based on an amount of fluid flowing through theflow sensor.
 4. The flow sensor of claim 3 further comprising a shaftconverting linear motion of the piston to rotational movement of theshaft.
 5. The flow sensor of claim 4 further comprising a first chamberhousing the shaft.
 6. The flow sensor of claim 5 further comprising aspring biasing the piston upstream in the combined flow guide and filterunit.
 7. The flow sensor of claim 4 wherein the flow indicator assemblyfurther comprises an indicator that points to indicia indicating thecurrent amount of flow through the flow sensor based on rotationalmovement of the shaft.
 8. The flow sensor of claim 7 wherein the flowindicator assembly includes a flow gauge to indicate a proper flowcondition.
 9. The flow sensor of claim 1 wherein the combined flow guideand filter unit is a single piece flow guide and filter.
 10. The flowsensor of claim 1 wherein the combined flow guide and filter has a meshscreen to filter debris from fluid.
 11. The flow sensor of claim 1further comprising a top cover that threads onto the body, the top covercarries the flow indicator assembly.
 12. The flow sensor of claim 1wherein the combined flow guide and filter has an annular base and anannular top.
 13. The flow sensor of claim 12 wherein the combined flowguide and filter has supports extending longitudinally from the annularbase to the annular top.
 14. The flow sensor of claim 13 wherein a meshscreen is associated with the supports.
 15. The flow sensor of claim 1further wherein the at least a frusto-conical portion includes a firstfrusto-conical portion and a second portion upstream of the firstfrusto-conical portion of the flow guide, the first frusto-conicalportion having a greater taper than the second portion.
 16. The flowsensor of claim 15 wherein the wherein the first frusto-conical portionand the second portion are contiguous.
 17. The flow sensor of claim 15wherein the second portion is a straight, cylindrical portion.
 18. Amethod of converting a filter assembly to a flow sensor and filterassembly comprising the steps of: removing a cover of a filter assembly;removing a filter basket from a body of the filter assembly; installinga combined flow guide and filter assembly in the body of the filterassembly, the combined flow guide and filter assembly having a hollowfrusto-conical portion; and installing a cap assembly in place of thecover, the cap assembly including a plunger operating inside at least aportion of the hollow frusto-conical portion of the combined flow guideand filter assembly and a flow indicator assembly that converts linearmovement of the plunger to a flow measurement.
 19. The method of claim18 wherein the flow indicator includes converting linear movement of theplunger to rotational movement of a flow indicator corresponding to aflow measurement.
 20. The method of claim 19 wherein the flow indicatorassembly includes a dial with indicia indicating amounts of flow beingmeasured.
 21. The method of claim 20 wherein the flow indicator assemblyis preassembled.
 22. The method of claim 21 wherein the cap assembly hasa thread connection to the body.
 23. A flow sensor comprising: a body; acombined flow guide and particulate filter unit associated with the bodyand including a flow guide portion and a particulate filter portion, theflow guide portion including an annular wall portion spaced from theparticulate filter portion and surrounded by the particulate filterportion, and the annular wall defines a passage for fluid to flowthrough; a piston moveable inside at least a portion of the tubularportion of the flow guide portion based on an amount of fluid flowingthrough the flow sensor; and a flow indicator assembly to indicate theflow through the flow sensor based on movement of the piston in thecombined flow guide and filter unit.